Migrating CXRC session clustering

To migrate the existing CXRC sessions from individual coupling to clustering, do the following steps:

1. Suspend the master session by using the TIMEOUT parameter and install the program temporary fix (PTF).
2. Issue the XCOUPLE PURGE command to clear the information about the individual sessions from the master session.
3. Modify the ANTXIN00 parmlib member to associate each data mover LPAR with a master session and a unique cluster name. To modify the ANTXIN00 parmlib member, use the ClusterMSession and the ClusterName parameters in the STARTUP category. Here is an example:

   STARTUP -
   ClusterMSession(TUCSON) -  
   Clustername(SYSTEM1 CLUSTER1 - SYSTEM2 CLUSTER2 - SYSTEM3 CLUSTER3)

4. Modify the parmlib to enable the cluster monitoring to data set (optional).
5. Allocate and initialize a cluster control data set for each LPAR that operates as a cluster. Use the following JCL as an example:

   //STEP1 EXEC PGM=IEBDG
   //SYSPRINT DD SYSOUT=*
   //DD1 DD DSN=mhlq.XCOPY.clustername.CLUSTER,
   // DCB=(RECFM=FB,LRECL=15360,BLKSIZE=15360,DSORG=PS)
   // SPACE=(CYL,(1,0)),STORCLAS=XRCSTATE,DISP=(NEW,CATLG)
   //SYSIN DD *
   DSD OUTPUT=(DD1)
   CREATE QUANTITY=30
   END

   Note: You cannot use the extended format data set. You can place the data set on the same volume as any state data set accessible by the cluster LPAR.
6. To collect the cluster-level monitor data, allocate a state data set for each cluster. Use the following JCL as an example:

   //STEP2 EXEC PGM=IEFBR14
   //DD1 DD DSN=mhlq.XCOPY.clustername.STATE,
   // DCB=(RECFM=F,LRECL=4096,BLKSIZE=4096,DSORG=PO),
   // DSNTYPE=LIBRARY,
   // SPACE=(CYL,(2,0,1)),STORCLAS=XRCSTATE,DISP=(NEW,CATLG)

   The data set must be a PDSE data set. The data set can be placed on the same volume as any state data set accessible by the cluster LPAR. In the XRC parmlib, ensure that the MONITOR category for each individual XRC session in the cluster has MonitorOutput(ON). If a MonitorWakeup value is specified, use the same value for all individual XRC sessions in the cluster.
7. You can attain the following results by changing the XRC parmlib to use a smaller SHADOW READDELAY value, such as 500:
   • Achieve more aggressive Recovery Point Objective targets.
   • Avoid delays from lightly loaded data movers in large scale configurations.
   Note: This operation results in higher CPU utilization during periods of non-peak workloads.
8. Issue the F ANTAS000,CREFRESH command to each LPAR to initiate cluster setup processing.
9. Restart individual sessions and resynchronize.
10. When duplex is reached, issue the XCOUPLE ADD command to couple individual sessions to the master session.
    Note: Do not use the cluster name in the XCOUPLE commands.

To migrate the existing CXRC sessions from clustering to individual coupling, do the following steps:

1. Suspend master session by using TIMEOUT parameter.
2. Issue XCOUPLE PURGE command to clear information about all individual XRC sessions that are previously coupled through the cluster.
3. Modify the ANTXIN00 parmlib member to specify ClusterMSession (DISABLED).
4. Issue F ANTAS000,CREFRESH command to restart the cluster setup processing and disable clustering.
5. Issue XCOUPLE ADD command to couple the individual XRC sessions to the master session.